(The ones pictured are made from inner flue pipe left over from the installation of a balanced flue boiler.)

The rings are trimmed so that when the ends are butted together, they just fit over their respective ends of the rack.

Firstly the rings are fitted inside the ends of the gaiters with the ends overlapping, and with generous amounts of rubber grease applied.

The rings are then pulled open, stretching the rubber, until the ends butt together and lock into place. This can require quite a bit of force, but it's a still lot easier than stretching the gaiter over the rack in a tight space...

The gaiters can then be slid over the track rods and onto the rack with ease.

Finally the ring is pulled clear and off the rack using the string handle, while holding the gaiter in position to make sure it drops into place into its groove.

Note: At the column end of the rack the ring has to be narrow enough to extract between the boss and the gaiter once it's in place. This means a little more care is required, but it's still quite easy.